Rename TypedConverter to SimpleConverter, enforce non-null source

Author: scordio

junit-platform-commons/src/main/java/org/junit/platform/commons/support/conversion/Converter.java

@@ -25,7 +25,7 @@
  * instances may potentially be cached and called from different threads, they
  * should be thread-safe.
  *
- * <p>Extend {@link TypedConverter} if your implementation always converts
+ * <p>Extend {@link SimpleConverter} if your implementation always converts
  * from a given source type into a given target type and does not need access to
  * the {@link ClassLoader} to perform the conversion.
  *
@@ -34,7 +34,7 @@
  *
  * @since 6.0
  * @see ConversionSupport
- * @see TypedConverter
+ * @see SimpleConverter
  */
 @API(status = EXPERIMENTAL, since = "6.0")
 public interface Converter<S, T extends @Nullable Object> {

junit-platform-commons/src/main/java/org/junit/platform/commons/support/conversion/TypedConverter.java renamed to junit-platform-commons/src/main/java/org/junit/platform/commons/support/conversion/SimpleConverter.java

@@ -17,53 +17,55 @@
 import org.junit.platform.commons.util.Preconditions;
 
 /**
- * {@code TypedConversionService} is an abstract base class for
- * {@link Converter} implementations that always convert objects of a
- * given source type into a given target type.
+ * {@code SimpleConverter} is an abstract base class for {@link Converter}
+ * implementations that always convert objects of a given source type into a
+ * given target type.
  *
  * @param <S> the type of the source argument to convert
  * @param <T> the type of the target object to create from the source
  * @since 6.0
  */
 @API(status = EXPERIMENTAL, since = "6.0")
-public abstract class TypedConverter<S, T extends @Nullable Object> implements Converter<S, T> {
+public abstract class SimpleConverter<S, T extends @Nullable Object> implements Converter<S, T> {
 
 	private final Class<S> sourceType;
 	private final Class<T> targetType;
 
 	/**
-	 * Create a new {@code TypedConversionService}.
+	 * Create a new {@code SimpleConverter}.
 	 *
 	 * @param sourceType the type of the argument to convert; never {@code null}
 	 * @param targetType the type of the target object to create from the source;
 	 * never {@code null}
 	 */
-	protected TypedConverter(Class<S> sourceType, Class<T> targetType) {
+	protected SimpleConverter(Class<S> sourceType, Class<T> targetType) {
 		this.sourceType = Preconditions.notNull(sourceType, "sourceType must not be null");
 		this.targetType = Preconditions.notNull(targetType, "targetType must not be null");
 	}
 
 	@Override
 	public final boolean canConvert(ConversionContext context) {
-		// FIXME TypeDescriptor.NONE handling?
-		// FIXME add test cases with subtypes
-		return this.sourceType == context.sourceType().getType() && this.targetType == context.targetType().getType();
+		// FIXME adjust for subtypes
+		return !context.sourceType().equals(TypeDescriptor.NONE) //
+				&& this.sourceType == context.sourceType().getType() //
+				&& this.targetType == context.targetType().getType();
 	}
 
 	@Override
 	public final T convert(@Nullable S source, ConversionContext context) {
+		Preconditions.notNull(source, "source cannot be null");
 		return convert(source);
 	}
 
 	/**
 	 * Convert the supplied {@code source} object of type {@code S} into an object
 	 * of type {@code T}.
 	 *
-	 * @param source the source object to convert; may be {@code null}
+	 * @param source the source object to convert; never {@code null}
 	 * @return the converted object; may be {@code null} but only if the target
 	 * type is a reference type
 	 * @throws ConversionException if an error occurs during the conversion
 	 */
-	protected abstract T convert(@Nullable S source) throws ConversionException;
+	protected abstract T convert(S source) throws ConversionException;
 
 }

jupiter-tests/src/test/java/org/junit/jupiter/params/converter/LocaleConverter.java

@@ -12,19 +12,18 @@
 
 import java.util.Locale;
 
-import org.jspecify.annotations.Nullable;
-import org.junit.platform.commons.support.conversion.TypedConverter;
+import org.junit.platform.commons.support.conversion.SimpleConverter;
 
 // FIXME move to ConversionSupportIntegrationTests
-public class LocaleConverter extends TypedConverter<String, @Nullable Locale> {
+public class LocaleConverter extends SimpleConverter<String, Locale> {
 
 	public LocaleConverter() {
 		super(String.class, Locale.class);
 	}
 
 	@Override
-	protected @Nullable Locale convert(@Nullable String source) {
-		return source != null ? Locale.forLanguageTag(source) : null;
+	protected Locale convert(String source) {
+		return Locale.forLanguageTag(source);
 	}
 
 }